碳纳米管和碳化硅对粉末冶金生产纯铝机械性能的影响外文文献

Please cite this article in press as Herzallah H et al Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy J Mater Res Technol 2019 https doi org 10 1016 j jmrt 2019 12 027 ARTICLE IN PRESS JMRTEC 1187 No of Pages 7 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx br Available online at Original Article Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy Heba Herzallaha Ayman Elsaydb c Ahmed Shasha d Mahmoud Adlya a Mechanical Design and Production Engineering Department Faculty of Engineering Cairo University 12316 Giza Egypt b Central Metallurgical Research and Development Institute Cairo Egypt c Osaka University Osaka Japan d Faculty of Engineering and Materials Science The German University in Cairo Egypt a r t i c l e i n f o Article history Received 20 September 2019 Accepted 9 December 2019 Available online xxx Keywords CNT SiC Aluminum matrix composites Powder metallurgy a b s t r a c t In the present research the effects of the size and amount of CNT and SiC particles on the mechanical properties of Al matrix composite were investigated SiC of particle size 10 m CNT 10 40 nm and Al powder of particle size less than 50 m and purity 99 99 were used Composites of Al with 3 6 9 and 12 wt SiC and 0 25 0 5 0 75 and 1 wt CNT were manufactured by powder metallurgy technique by cold compaction and vacuum sintering Relative density hardness compression and friction coeffi cient were studied The results of scanning electron microscope SEM and optical microscope observations illustrated that the distribution of the reinforcing particles was uniform Moreover increasing the amount of SiC and CNT leads to decreasing the relative density and improving the hardness and compressive strength of Al SiC and Al CNT composites 2019 The Authors Published by Elsevier B V This is an open access article under the CC BY NC ND license http creativecommons org licenses by nc nd 4 0 1 Introduction Recently very advanced materials are spread worldwide to achieve special product requirements This is because a sin gle material generally cannot achieve the requirements of all engineering fi elds For this reason researchers have done efforts to use composite materials with unique properties So in the recent years there was a tremendous increase in production of metal matrix composites MMCs and their applications 1 In the last decades many research papers studied aluminum matrix composites AMCs The mechani Corresponding author E mail aymanhamada cmrdi sci eg A Elsayd cal properties of pure aluminum such as ductility and strength give pure aluminum matrix composite possibility of utiliza tion in advanced applications The major barrier to use aluminum in advanced engineer ing applications is its low wear resistance So adding ceramics and carbon nanotubes CNTs to aluminum matrix would amend the wear resistance hardness strength and corrosion resistance 2 3 The reinforcement is the principal provider of optimum mechanical and electrical properties in the com posite materials There are many types of reinforcements such as fi bers fl akes wires foams whiskers particulates foils etc Ceramic particle reinforcement was shown as bet ter than fi ber type in terms of mechanical properties and microstructure by optimizing volume fraction and particle size of reinforcement 4 Carbon nanotubes CNTs either multi https doi org 10 1016 j jmrt 2019 12 027 2238 7854 2019 The Authors Published by Elsevier B V This is an open access article under the CC BY NC ND license http creativecommons org licenses by nc nd 4 0 Please cite this article in press as Herzallah H et al Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy J Mater Res Technol 2019 https doi org 10 1016 j jmrt 2019 12 027 ARTICLE IN PRESS JMRTEC 1187 No of Pages 7 2 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx walled MWCNT or single walled SWCNT are extensively used worldwide in recent years as the perfect reinforce ments for composites because of their extra high strength 30 100 GPa and high elastic modulus around 1 TPa and also good electrical and thermal properties 5 9 By consolidating CNT with aluminum metal matrix it will produce compos ite with enhanced properties Combination of CNTs with light metals such as aluminum leads to strong but light composites convenient for the sports industries the aerospace or automo tive industries where the weight reduction and fuel economy are the fi rst priority 10 11 To obtain the expected high effec tiveness of CNT Al composites the composite microstructures and their effects on resultant properties must be studied 12 13 SiC particles have been generally chosen as the rein forcement phase for many applications 14 15 This is due to its high hardness wear resistance and excellent high tem perature properties as well as its low cost Furthermore SiC at high temperatures does not react with the matrix 16 To produce metal matrix composites powder metallurgy is con sidered as the best technique The main advantage of powder metallurgy compared to melting techniques is its low process ing temperature Thus there is no interaction between the matrix and the reinforcement phases 17 Another advantage of powder metallurgy technique is its ability to manufacture near net shape products with low cost 18 19 Furthermore powder metallurgy technique offers the ability to manufacture high melting point advanced superelastic and shape memory alloys like Ti Ta and Ti Nb alloys with very good properties 20 21 Omyma El Kady and A Fathy stated that increasing the amount and reducing the particle size of SiC in AL matrix decreases the grain size reduces the thermal conductivity and increases the hardness and compressive strength 22 Sambit Kumar Mohapatra and KalipadaMaity have studied the mechanical and tribological properties of hot extruded aluminum metal matrix by powder metallurgy and found an improvement in density compressive strength and micro hardness due to the fi ne distributed graphite particles which act as solid lubricant and decrease wear rate 23 Jaswinder Singh has studied various aspects concerning the fabrication and wear properties of Al SiC Gr hybrid composites Graphite Gr particles signifi cantly enhance the wear properties The hybrid reinforcements can be successfully incorporated into the Al matrix by powder metallurgy It was also shown that the presence of SiC particles increases the hardness of the com posites The wear resistance of Al Sic Gr composites increases with the addition of Gr 24 The work done by V Umasankaret et al to study the sintered aluminum metal matrix composite reinforced with different weight percentages of SiC particles has highlighted the signifi cance of processing parameters on sintered density hardness and consequent breaking load 25 OlehBoshko et al developed a method for production of a new nanocomposite material comprising iron copper and multi walled carbon nanotubes with a high ultimate tensile strength 26 Shisheng Li et al revealed the possibility to achieve a uni form distribution of carbon nanotube CNT reinforcement in aluminum matrix by novel nano micro sized hybrid reinforce ments with CNT growing on the surface of SiC particle SiCp synthesized by chemical vapor deposition SiCp CNT Al com posite exhibited both improved elastic modulus and tensile strength mainly because CNT was dispersed uniformly and achieved intimate interfaces with Al matrix with the help of well dispersed SiCp 27 The current work aims at studying the effect of the amount of CNT and SiC on the mechanical properties of Al matrix com posites synthesized by using powder metallurgy technique The prepared samples were investigated by the microstruc ture SEM and optical The relative density and compression strength of the samples were studied The idea of perform ing compression test was taken from the applications of such parts under compressive loads such as upsetting the extent to which a material can be deformed in special metal working process without the initiation of cracks 2 Experimental procedure CNTs were used with average particles sizes of 10 40 nm at 0 25 0 5 0 75 and 1 wt concentrations while the particle size of SiC is 10 m at 3 6 9 and 12 wt concentrations The average size of aluminum particles was 425 m with a purity of 99 99 The aluminum matrix and reinforcement particles were mixed for 20 min with 10 ml cyclohexane for each 20 gm of the composite powder as a control agent and 0 5 wt paraffi n wax which was used as a lubricant to facili tate cold compaction The samples were compacted at 560 MPa using a single action uniaxial hydraulic press of 20 ton capac ity The green compact samples were sintered in a vacuum furnace at 600 C for 3 h using the heating rate of 5 C min The actual densities of the manufactured samples were measured by using the Archimedes method ASTM B962 13 and compared with theoretical densities to obtain the rela tive densities Furthermore the samples were prepared for microstructure examination and the microstructure evolu tions were examined by using optical and scanning electron microscopes and X ray diffraction The compression test was performed on the manufactured samples of cylindrical cross section of 9 mm diameter and 15 mm height by using a Universal test machine model UH 500 KNA Schematize at the room temperature and under a speed of 2 mm min The wear tests of the sintered specimens were carried out using a pin on disc tribometer model TE 79 multi Axis tribometer The tested specimens were in the form of a cylinder of 20 8 mm The specimens were loaded against the ring under normal loads of 10 N at sliding speed of 250 rpm for 15 min The Vick ers hardness Hv was measured as the average of 5 readings along the cross section of polished surface of the specimen using Zwick Roell hardness tester using the load of 1 kg and the holding time of 15 s The samples were tested according to Vickers testing as per ISO 6507 3 Result and discussion Table 1 represents the calculated relative densities of the man ufactured composites at different SiC and CNT concentrations As can be seen from this table the relative densities of the manufactured samples decrease with increasing the SiC frac tions It is also observed that the highest SiC percent i e 12 gives the lowest relative density value This may be attributed Please cite this article in press as Herzallah H et al Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy J Mater Res Technol 2019 https doi org 10 1016 j jmrt 2019 12 027 ARTICLE IN PRESS JMRTEC 1187 No of Pages 7 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx 3 Table 1 The calculated relative densities of Al matrix composite at various SiC and CNT concentrations Samples Relative density AL 98 5 Al 3 wt SiC97 9 Al 6 wt SiC 96 6 Al 9 wt SiC 95 Al 12 wt SiC 92 2 Al 0 25 wt CNT 97 Al 0 5 wt CNT 96 7 Al 0 75 wt CNT 96 3 Al 1 wt CNT 96 Fig 1 Hardness values of Al SiC composite to the good bonding and homogeneity of both matrix and rein forcement particle On the other hand the calculated relative densities at different CNT concentrations also follow simi lar trend Generally the relative densities of the composites containing various amounts of SiC and CNT show very high values which refl ects the good conditions that have been selected for the performed process like the compaction pres sure temperature and mixing time The experimental results of the hardness of Al SiC com posites are demonstrated in Fig 1 As can be seen from the fi gure increasing SiC volume fractions leads to the higher hardness values giving the best value at 12 SiC volume frac tion This may be attributed to the strengthening effect of the hard SiC particles and their higher hardness value The high est hardness value is 69 HV at 12 SiC while the lowest one is 53 HV at 3 SiC which is higher than that of pure Al On the other hand the Vickers hardness values of the Al CNT compos ites are depicted in Fig 2 It is clear that the hardness values increase with increasing the CNT volume fractions It is notice able that the increase of hardness of Al composites by CNT reinforcement is less than that of reinforcement by SiC The manufactured samples of Al with the reinforcement particles were subjected to compression test to study the effect of SiC and CNT volume fractions on the ultimate and yield compressive strength of the composites Fig 3 shows the stress strain curves of Al SiC composite samples As can be observed from the fi gure the higher SiC volume fraction val ues i e 9 No of Pages 7 4 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx Fig 6 Friction coeffi cient of Al CNT composite Fig 4 It is noticed that the CNT volume fractions have small effect on the compression strength values However increas ing CNT volume fractions resulted in observable softening which may be due to the void formation effect of CNT Fig 5 demonstrates the friction coeffi cients of Al SiC com posite samples at different SiC volume fractions As can be observed from the fi gure shown the friction coeffi cients of the manufactured samples are improved by increasing the SiC volume fractions They are all lower than that of pure Al sample On the other hand the Al CNT composites friction coeffi cients are presented in Fig 6 The Al composite sam ples containing CNT have shown very similar values among each other implying that the used CNT percentage levels have very similar effects on the friction coeffi cient of the composite However all the samples of Al composites have shown much improved coeffi cient of friction compared to that of pure Al sample Figs 7 and 8 demonstrate the optical micrographs of Al SiC and Al CNT composites As can be observed from the pre sented fi gures the higher the SiC volume fraction the highly particles distribution through the aluminum matrix occurs A slight grain refi nement effect can also be observed from Fig 7 On the other hand Fig 8 shows that the introduction of CNT into the microstructure of Al composites have shown successive and consistent grain refi nement until the CNT per centage reaches 0 75 wt After that and at the percentage of 1 wt the CNTs are considerably agglomerated which elim inates their effects on the structure which eventually results Fig 7 Optical micrographs of Al SiC composites Please cite this article in press as Herzallah H et al Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy J Mater Res Technol 2019 https doi org 10 1016 j jmrt 2019 12 027 ARTICLE IN PRESS JMRTEC 1187 No of Pages 7 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx 5 Fig 8 Optical micrographs of Al CNT composites Fig 9 EDS analysis of Al 3 wt SiC composite a revealing 100 Al at the matrix point 1 and 26 Al 34 Si 36 C 4 O at the SiC particle point 2 and Al 1 wt CNT composite b revealing 100 Al at matrix point 3 and 65 Al 35 C at point 4 in the formation of coarse grains similar to those of pure Al sample The manufactured composite samples of aluminum matrix have been analyzed to check the percentage of the elements inside the composite structure Fig 9 depicts the EDS analysis of Al 3 SiC and Al 1 CNT composites at two points As can be observed from this fi gure at point 2 the analysis gives a mixture of 26 Al 34 Si 36 C 4 O This analysis refl ects the good mixing of Al matrix and SiC particles while the existence of oxygen may be due to the oxidation of aluminum during the sample preparation as Al can be easily oxidized More over at point 1 the analysis produces fully 100 aluminum On the other hand the EDS analysis of Al 1 CNT is represented in Fig 9 b It is observed that the CNT are homogenously distributed through Al matrix as can noticed from point 4 anal ysis It is also noticeable that the pure aluminum is found in the analysis of point 3 The XRD analysis of Al 12 SiC and Al 1 CNT has been evaluated to check the phase structure formed during the powder metallurgy process As demonstrated in Fig 10 there are no phases formed during the sintering process other than the original pure Al and SiC particles It is also worth men tioning that the percentage of CNTs are very low 1 wt maximum to be observed in the XRD pattern of Al CNT com posite sample Please cite this article in press as Herzallah H et al Effect of carbon nanotubes CNTs and silicon carbide SiC on mechanical properties of pure Al manufactured by powder metallurgy J Mater Res Technol 2019 https doi org 10 1016 j jmrt 2019 12 027 ARTICLE IN PRESS JMRTEC 1187 No of Pages 7 6 j m a t e r r e s t e c h n o l 2 0 1 9 x x x x x xxx xxx Fig 10 XRD analysis of Al 12 SiC and Al 1 CNT 4 Conclusions The pure Al samples Al SiC and Al CNT composites were manufactured by powder metallurgy technique The below conclusions may be drawn from the presented results Both CNTs and SiC particles could be homogeneously dis tributed in the structure of the Al composites by the use of wet mixing The XRD analysis did not show any further structure formed during powder metallurgy process which refers that there is no solid state reaction happened between Al and CNT or SiC The density values for the prepared Al SiC composite indi cated that the densifi cation decreases by increasing SiC and CNT contents Both the hardness and the compressive strength for sam ples increases compared to pure Al by increasing CNT 161 381 7 2 Torres B Lieb lich H Ibanez J Garcia Escorial A Mechanical properties of some PM aluminide and silicide reinforced 2124 aluminum matrix composites Scr Mater 2002 47 45 50 3 Sahin Y Murphy S The effect of fi bre orientation of the dry sliding wear of borsic reinforced 2014 aluminum alloy J Mater Sci 1996 34 5399 407 4 Dobrzanski LA Wlodarczyk A Adamiak